How should I setup 3x90 mm fans in my PC case to get the best airflow?

[Guest]

Just wanted to get your guys' opinion on the fan setup. I have spaces for 2x 90 mm fans on the left window and another space for a 90mm fan at the back. How should I install fans there to get the best airflow. Keep in mind that my PSU fan also acts as an outtake.

 

[atljsf]

what case do you have, normally the psu will not act as a fan if it goes on the bottom of the case

what hardware do you have on the case?

 

[Guest]

I have this case : https://zebronics.com/products/cabinet-budget/slam

My PSU is installed at the top so it blows out the air from the case.

System Specifications :
CPU : i3 4150
GPU : GTX 750Ti
MOBO : Asus H81M CS
RAM : Kingston HyperX 8GB DDR3
HDD : Toshiba 1TB (7200RPM)
PSU : Antec BP450S

 

[atljsf]

one in in the front and one out in the back should be more than enough for those parts, none under load will generate any considerable amount of heat, perhaps the gtx and won't reach easily 60°c

be sure to do a decent cable management with the psu cables and check temperatures with hwmonitor or openhardwaremonitor after installing the two fans, you might find that the one in the back for that case makes noise, so perhaps only one in the front or two, but you need to experiment temperatures under load, the one in the back thanks to the shape of the grid proably will make some noise and you will hear it, i think

one recommendation, get another 8 gbs of ram, so you work in dual channel mode, cpu should run better accessing the ram, or 2x4 gbs of ram on dual channel

 

[Guest]

one in in the front and one out in the back should be more than enough for those parts, none under load will generate any considerable amount of heat, perhaps the gtx and won't reach easily 60°c

But I don't have any fan mounts at the front of the case, just 2 in the left window and 1 at the back. (Read the description of this thread)
I have been gaming on this PC without any fans for about an year but lately I got to know that the temperature of the GPU hits around 74 °C while gaming. So now I am worried. Please suggest me the best fan configuration for this scenario.

 

[Aeacus]

Here's how i'd do it:

2x 90mm side as intake (to bring fresh cold air in for GPU and CPU), 1x 90mm rear as exhaust (to expel excess heat alongside PSU fan).

I've used side fans as intake on my AMD build as well (full specs in my sig). Side intakes do help to cool GPU and CPU better than without side intakes at all.

Edit: Forgot that my Haswell build (full specs in my sig) also has 2x 120mm side intake fans to keep system cool, despite it also having 2x 120mm front intake, 1x 120mm bottom intake, 1x 120mm rear exhaust and 1x 120mm top exhaust.

 

[atljsf]

i confused the picture, i did read your post and watched the pictures, that is where i got confused

most gpus can read 90°c and work well, 74 means not much for that card

after you install the fans we mentioned, remember to do a good clean of the machine

with that particular card is possible that is more beneficial to put those cans taking air out

but that would be 3 fans doing negative pressure but with your hardware and this case, that might not be bad at all

as i said, install them in two configurations, one in the side and one in the back, try under load to put the one in the side pulling air in and then try it pushing air out

being 90mm fans, you can put 2 in the left panel, but 2 will be very noisy, 1 is noisy enough

 

[Aeacus]

i confused the picture, i did read your post and watched the pictures, that is where i got confused

most gpus can read 90°c and work well, 74 means not much for that card

after you install the fans we mentioned, remember to do a good clean of the machine

with that particular card is possible that is more beneficial to put those cans taking air out

but that would be 3 fans doing negative pressure but with your hardware and this case, that might not be bad at all

as i said, install them in two configurations, one in the side and one in the back, try under load to put the one in the side pulling air in and then try it pushing air out

being 90mm fans, you can put 2 in the left panel, but 2 will be very noisy, 1 is noisy enough

By looking where the side fan mounts are, one can tell that lower fan would end up just beneath the GPU and upper fan would be above the GPU, facing CPU.

Since hot air rises, it's better to bring cold air in from bottom and expel it from the top.

If the lower fan would be exhaust then it could choke the GPU. I'd still mount the bottom fan as intake to bring more cool air in for GPU to "consume".

Since OP probably uses stock CPU cooler and not an aftermarket heatsink, i'd mount the upper side fan also as intake for bringing in the cool air for CPU to "consume". If the OP would have aftermarket heatsink on CPU (e.g like in my Sklake build) then i'd either mount the top fan as exhaust or leave the fan spot completely empty.

Just because fan is 90mm doesn't instantly mean it's loud. Fan loudness depends on the fan used but mostly the RPM of said fan. For example: Noctua NF A9x14 PWM (92mm) fan can do up to 2200 RPM and that with only 19.9 dB(A).
specs: http://noctua.at/en/products/fan/nf-a9x14-pwm/specification

19.9 dB(A) @ 2200 RPM is actually very quiet. For comparison, i'll take my Corsair ML140 Pro (140mm) case fan that does 37 dB(A) @ 2000 RPM.
specs: http://www.corsair.com/en/ml140-pro-led-red-140mm-premium-magnetic-levitation-fan

If i were to decrease the RPM of my ML140 fan to about 400 RPM then i'd be looking at 16 dB(A) from it.

 

[atljsf]

all positive? interesting, another option to try and verify how it works under load

 

[Aeacus]

With positive pressure, less dust enters the system since all excess hot air escapes through every little hole the case has.

With negative pressure, you'll create vacuum effect where air is sucked in from every little hole the case has and thus more dust enters the system.

To keep case clear from dust, it's easier to filter the intake fans in positive pressure system than trying to filter all the small holes (including the mesh panels case has) when negative pressure system is used.